Forces loyal to Libyan dictator Moammar Gadhafi reportedly broke through rebel lines at an opposition-held city in fighting early Saturday that killed at least 30 people, witnesses said.

A doctor in the city told Reuters that mostly civilians were killed during the latest round of fighting for control of Zawiya, 50 kilometres west of the capital Tripoli.

The BBC reported that rebel fighters pushed government forces out of the city centre, before the army launched a second attack, using tanks to shell Zawiya's central square.

The battle for Zawiya could prove crucial to the regime's defence of the Libyan capital and for control of the nearby Tunisian border.

Residents said snipers are shooting at anyone on the streets and several fires are raging across the city.

"Please let the world know that we need some help. They have surrounded the city," a man who lives in Zawiya said. "Right now we hear a lot of heavy fighting. It's non-stop."

The rebels' setback in the battle for the city was the second in as many days.

A large arms and ammunition depot outside the city of Benghazi, the largest city in the rebel-held east of the country, blew up Friday in a massive explosion that completely destroyed an area three times the size of a soccer field.

Ambulance drivers who rushed to the site reported that at least 26 people were killed in the blast, which levelled several buildings, cars and trees.

It was not immediately clear how the depot blew up, but suspicion immediately fell on Gadhafi agents seeking to deny the rebels the arms and ammunition they need to fight their way westward toward the Gadhafi-held city of Sirte on the Mediterranean coast.

Residents join fight in port city

The rebels, however, fared better elsewhere, capturing the key oil port of Ras Lanouf from pro-Gadhafi forces in their first military victory in a potentially long, westward march from the east of the country to the capital Tripoli hundreds of kilometres to the west.

One of the rebels, Ahmed al-Zawi, said the battle was won after Ras Lanouf residents joined the rebels, who were armed with anti-aircraft guns and rocket-propelled grenades.

Exactly. Its funny to me that people think Gadhafi can't take the cities he wants when he wants. Since its a fact that a majority of the rebels aren't armed, what are they supposed to do when mercenaries approach in a staggered formation armed with assault rifles and what not? They can't do ****, man you got to feel their pain though. Even with thousands dead, the rebels are brave enough to remain in the streets

Exactly. Its funny to me that people think Gadhafi can't take the cities he wants when he wants. Since its a fact that a majority of the rebels aren't armed, what are they supposed to do when mercenaries approach in a staggered formation armed with assault rifles and what not? They can't do ****, man you got to feel their pain though. Even with thousands dead, the rebels are brave enough to remain in the streets

he has to walk a fine line.

he's trying to be strong enough to stay in power but not so brutal there's no turning back.

he doesn't want to go back to being the pariah from the 80's.

and this time he doesn't have the soviet union and a few arab/african countries on his side.